Electric fuse assembly



Aug. 27, 1940.

P. c. HERAULT 3,164

ELECTRIC FUSE ASSEMBLY Filed Aug. 13, 1937 2 Sheets-Sheet 1 Aug. 27, 1940. P. c. HERAULT 2,213,164

ELECTRIC FUSE ASSEMBLY Filed Aug. 13, 1937 2 Sheets-Sheet 2 Patented Aug. 27, 1940 UNETEQ ELECTRIC FUSE ASSEMBLY Pierre 6. Hera-alt, Atlanta, Ga, assignor to Tomlinson F. Johnson, doing business as Johnson l'vlfg. ilo Atlanta, Ga.

Application August 13, 1937, Serial No. 158,999

10 Gianna.

This invention relates to multiple drop out fuses of the general type disclosed in a pending application of T. F. Johnson, i-To. 21. 14, 1935 and, among other objects, air a relatively simple, cheap and durable -rt shot fuse assembly wherein snap-action Transfer switches are associated with the fuses and are adapted to be tripped and closed in succession as the fuses are blown. The idea is to provide a simplified fuse assembly especially adapted for use on rural electrification lines.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawings, wherein:

Fig. l is a side elevation of a fuse assembly embodying the invention;

Fig. 2 is a sectional View taken on the line 2--2 of Fig. 1;

Fig. 3'is a front elevation of the fuse assembly shown in 1;

Fig. 4 is a sectional view taken on the line l l of Fig. 2 and shown on an enlarged scale; and

Fig. 5 is a sectional view taken on the line of Fig. 2 and shown on an enlarged scale.

Referring particularly to the drawings, the drop out fuse assembly is shown as being applied to a cross arm in of an ordinary pole type transmission line. However, it is to be understood that it may be mounted on any suitable support. In this example, it is carried by a suitable metal bracket ll clamped on the cross in the same manner as disclosed in said pending application. The bracket 5 l is somewhat resilient is shown as being bolted at its lower end to a clamp l2 which carries a single bushing type insulator it like that shown in the patent to Johnson, No. 2,074,913. In the illustrative embodiment the entire fuse assembly is shown as being carried by this single insulator; although it is to be understood that similar fuse assemblies may be supported on separate insulators.

Referring to Figs. 1 and 3, the upper end. of the insulator carries a metal cross bea or bar M to whichis connected a plurality spring arms 55, one for each fuse and the spring arms carry hood shaped contacts l5 for the respective fuses. A transmission conductor l? is adapted to be connected to the cross bar by means of an ordinary clamp H3.

The lower end of the insulator carries a metal bracket l9 which has a collar supporting an insulating tube or cross bar 25 of any suitable material arranged slightly forwardly of the lower end of the insulator. This insulating tube or cross bar serves to support the lower ends of the fuse units and the snap switches which connect them in succession. In this example, metal collar brackets 22 and 23 are secured to the opposite ends of the insulating tube and are insulated 5 from each other. The bracket 22 carries a suitable clamp 2 for connecting it to the conductor 25. The collar 29 and the collar brackets and 23 are shown as having forwardly extending ears or flanges 26 to which are secured forwardly pro- 10. jecting arms 2'! substantially parallel with the respective contact-carrying arms 65 at the top. Each of the lower arms carries forked bearing brackets or hinge elements for removably supporting the respective fuse units. Each switch 15 fuse unit is shown as comprising an ordinary insulating fuse tube 29 having a clamping collar 38 secured near its lower end on which is pivotally mounted a cast metal or toggle like member 35 having trunnions 32 adapted to rest in the 2 hinge members. Each fuse tube carries a removable fuse element or wire adapted to be secured under slight tension by means of a thumb nut 3 to the toggle like member l. Also, the link member carries a hook eye 35 on its rear face 25 extending upwardly at an angle and arranged to limit the swinging movement of the tube in the link member. Furthermore, this eye serves as a means for removing the fuse unit after it is blown and swung to its dropped-out position. 3Q The upper end of each fuse tube carries an ordinary metal ferrule having a hook eye 3? on its forward portion adapted to be engaged by an ordinary switch hook to swing the fuse unit to its closed position. Theupper end of the ferrule 35 has an ordinary removable screw cap constituting the upper terminal of the fuse unit and adapted to engage upper contact member it: In Figs. 1 and l, the hook eye 35 is shown as engaging an upstanding'bent leaf spring 33 which serves to 40 exert some outward swinging pressure on the fuse unit and also makes good electrical contact between the lower fuse bracket and the fuse element. The'structure of the fuse units here described more or less generally is preferably substantially identical with that shown in the aforesaid Johnson patent.

In the aforesaid Johnson application the separate fuse units are connected successively in the circuit by of a time delayed switch having a. blade held open by the first fuse tube and biased to be closed by a spring when this fuse tube drops out. Naturally, the spring pressure on the switch blade was limited because of its tendency to swing out the fuse tube which holds it closed. In accordance with this invention, the fuse connecting switches are arranged independently of the fuse tubes and are adapted tobe cocked and tripped by the momentum of the drop out fuse units. The arrangement is such that the fuse units have to swing to their lowermost position before tripping the fuse connecting switches, thus permitting some delay before the switch closes.

Referring to Figs. 2, 3 and 4, the lower support for one of the fuse units at one end of the insulating bar 2| is shown as having a switch supporting bracket 39 presenting downwardly extending ears 40 between which there is pivotally mounted a switch blade 4|. The bracket, which is riveted or otherwise secured to the arm 21 also has an ear or lug 42 carrying a tensionspring 43 secured to an arm 44 on the lower edge of the switch blade and normally biasing this switch to its closed position. It is to be understood, however, that other types of springs may be employed for this purpose. The switch blade is shown as having a conical seat or contact portion 45 which cooperates with a conical head 46 on an adjustable contact bolt 41 carried by a bracket 48 on the next adjacent fuse support which also carries a switch like the one just described to close the circuit between the middle arm and the outside arm through another contact 46, as will later be explained.

The switches are adapted to be cocked in open position by means ofmovable cam trip latches 49 suitably secured on plungers or bars 50 and arranged to engage the upper edges of the respective blades. In this instance, the bars carrying the latches are slidably mounted in spaced ears 5| depending from the blade supporting brackets and the latch elements are prevented from rotating by guide pins 52 between said ears. The rods or bars 50, carrying the latches, project forwardly through the front ears and have fork shaped triggers 53 secured to their forward ends. Coil springs 54 are arranged between the rear faces of the'triggers and the front ears normally biasing the latches toward their switch locking positions as clearly shownin Fig. 4. In this example, depending strap metal stop members 55 are shown as being secured to the switch brackets andproject between the forward ears and the rear ends of the coil springs 54. The arrangement is such that when the switch blades are opened by engagement of a switch hook with eyes 56 on the blades, their opening or downward swinging movement is limited by the stop members. As soon as the blades clear the latch members they are locked automatically by the action of the compression springs 54 on the triggers. It will be understood that when one of the fuse units blows, say, the left hand fuse unit in Fig. 3, the yoke shaped link member 3| will strike the ends of" the fork shaped trigger and force itrearwardly. It engages the trigger adjacent to the pivotal connection between the link member and the collar 30 on the fuse tube. Incidentally, the fork shaped triggers provide clearance for the free lower ends of the fuse tubes. As soon as the switch blade is released, it snaps closed and its inside edge rides on the cam face of its latch, holding the latch out of its path with the trigger spring slightly compressed. After the first fuse unit is blown and the switch is closed as just described, the circuit through the second" fuse unit is completed, current passing through, the, middlefuse element and the switch blade out through the conductor 25. Likewi the circuit will be closed through the third fuse unit when the middle fuse unit blows, current passing through both of the switch blades in that instance. Incidentally, a cone contact member 46 for the second switch is secured to a bracket 51 on the lower face of the third fuse supporting arm. Since this third or last fuse unit does not trip a switch, it is provided with a spring bumper arm 58 like that shown in the aforesaid Johnson patent.

To avoid the possibility of burning the switch contacts due to arcing, the brackets carrying the cone contact members 46 are shown as having U-shaped outwardly flared spring blades 59 acting as arcing horns for the ends of the switch blades when they approach their closed positions or are being opened with a switch hook.

From the foregoing description, it will be apparent that the improved fuse assembly is very simple and rugged in its construction. Blown fuses are easily detected and replaced. The principal parts may be used interchangeably ,in either single or multiple fuse assemblies. The connecting switches are easily applied and are positively tripped by the fuse units. They are easily accessible and can be cooked by using an ordinary switch hook. In fact, this type of drop out fuse assembly can be used instead of some of the far more expensive and complex switch fuses now employed on high tension transmission systems.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shown and described. Moreover, it is not indispensable that all the features of the invention be used conjointly, since they may be employed advantageously in various combinations and subcombinations.

What is claimed is:

.1. In a multiple fuse assembly of the class described, a plurality of drop out fuse units; snapaction switches for connecting the fuse units successively in circuit; and spring actuated triggers for said switches connected to be struck and tripped by the fuse units after they have dropped out.

2. In a multiple fuse assembly of the class described, a plurality of drop out fuse units; snapaction switches for connecting the fuse units successively in circuit; releasable latch means for holding said switches open; and spring actuated triggers connected to release said latches arranged in the path of and operable by said fuse units when they reach their dropped out posi-a tions.

3. In a multiple fuse assembly of the classdescribed, a plurality of drop out fuse units; snapaction switches biased to connect the fuse units successively in circuit; and trigger plungers connected to release the respective switches and adapted to be struck and operated by the fuse units after they drop out.

4. In a multiple fuse assembly of the class described, a plurality of drop out fuse units; a sin-- except one of said units; and spring actuated triggers for said switches connected to be tripped by the fuse units when they are blown and drop out, whereby successive fuses are connested in the circuit.

6. In a multiple drop out fuse assembly of the class described, an upper horizontal metal bar carrying switch contacts; a lower horizontal bar of insuling material parallel with said upper bar carrying metal supports and hinge members; drop out fuse units removably journaled in said hinge members having terminals cooperating with said upper switch contacts; depending spring urged snap-action switches mounted on said metal supports arranged to close the circuit through successive fuse units as the fuses are blown; and spring actuated trigger controlled latch means for said switches connected to be released by the drop out movement of the corresponding fuse units.

7. In a multiple drop out fuse assembly of the class described, an upper horizontal metal bar carrying switch contacts; a lower horizontal bar of insulating material parallel with said upper bar carrying metal supports and hinge members; drop out fuse units removably journaled in said hinge members and having terminals cooperating with said upper switch contacts; snap-action switches carried by said supports arranged to close the circuit through successive fuse units as the fuses are blown; and trigger controlled latch means for holding the switches open and connected to be tripped by dropped out fuse units.

8. In a multiple drop out fuse assembly of the class described, an upperhorizontal metal bar carrying switch contacts; a lower horizontal bar of insulating material parallel with said upper bar carrying metal supports and hinge members; drop out fuse units removably journaled in said hinge members and having terminals cooperating with said upper switch contacts; snap-action switches carried by said supports arranged to close the circuit through successive fuse units as the fuses are blown; trigger controlled latch means for holding the switches open and connected to be tripped by dropped out fuse units; and eyes on said switches whereby they may be cocked open by using an ordinary switch hook.

9. In a multiple fuse assembly of the class described, a plurality of drop out fuse units; and trigger controlled, snap-action switches associated with said fuse units to close the circuit through successive units incident to the drop out movements of the respective units, said switches having cone and socket contacts.

10. In a multiple fuse assembly of the class described, a plurality of drop out fuse units; and trigger controlled, snap-action switches associated with said fuse units to close the circuit through successive units incident to the drop out movements of the respective units, said switches having adjustable cone and socket contacts and rcing members associated with said contacts to prevent arcs from burning the contacts.

P. C. HERAULT. 

